I am using EPE and Barbershop. I may have edited the headwear to "No Headwear", which I mention only because I saw the database conflict message.

*Error Log:

[15:36:12][jomini_script_system.cpp:276]: Script system error!
Error: marry effect [ Uffe Juel of (Internal ID 50502892) is not allowed to marry Keratza Theodorokanos-Zherkovo of (Internal ID 67265803) ]
Script location: file: events/dlc/ep2/wedding_events/ep2_wedding_events.txt line: 674


[14:15:31][jomini_script_system.cpp:276]: Script system error!
Error: Undefined event target 'diarch'
Script location: file: common/scripted_effects; invalidate_diarch_grand_wedding_effect line: 2
file: common/on_action/diarchy_on_action.txt line: 126

[14:15:31][jomini_script_system.cpp:276]: Script system error!
Error: Event target link 'scope' returned an unset scope
Script location: file: common/scripted_effects; invalidate_diarch_grand_wedding_effect line: 2
file: common/on_action/diarchy_on_action.txt line: 126

14:15:31][jomini_script_system.cpp:276]: Script system error!
Error: Undefined event target 'diarch'
Script location: file: common/scripted_effects; invalidate_diarch_grand_wedding_effect line: 2
file: common/on_action/diarchy_on_action.txt line: 126


[14:15:31][jomini_script_system.cpp:276]: Script system error!
Error: Event target link 'scope' returned an unset scope
Script location: file: common/scripted_effects; invalidate_diarch_grand_wedding_effect line: 2
file: common/on_action/diarchy_on_action.txt line: 126

*Debug Log:

jomini_effect_impl.cpp:443]: file: events/dlc/ep2/wedding_events/ep2_wedding_events.txt line: 669: Unop: ep2_wedding.0151 => They are already considered married !

*Database conflicts:

[09:46:51][gamedatabase.h:325]: Overriding entry 'm_headgear_spec_ep2_byzantine_wedding' for database 'gfx/portraits/accessories' in ' file: gfx/portraits/accessories/x_headgear.txt line: 46'
[09:46:51][gamedatabase.h:325]: Overriding entry 'f_headgear_spec_ep2_byzantine_wedding' for database 'gfx/portraits/accessories' in ' file: gfx/portraits/accessories/x_headgear.txt line: 1033'